Small Outline Dual Inline Memory Module

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What Does Small Outline Dual Inline Memory Module Mean?

Small outline dual inline memory module (SO-DIMM) is a type of computer memory that is smaller than the regular DIMM used in desktop PCs. SO-DIMM uses the same circuitry and microchips as other memory modules, but is made in a smaller form factor to fit devices that do not have much space such as laptops, high-end printers, enterprise-grade networking hardware and even small-form-factor PCs like those that use mini-ITX motherboards.


Techopedia Explains Small Outline Dual Inline Memory Module

SO-DIMMs are noticeably smaller than regular DIMMs, about only half the length of the latter. However, they are more or less equal in power and voltage ratings to DIMMs, so their small size does not necessarily mean that they have lower memory capacities or lower performance. Their smaller size means that device manufacturers can easily design them into their devices without problem. Laptops usually have user-accessible SO-DIMM slots on the bottom, but slots are sometimes located in different places depending on the brand and model.

The first SO-DIMMs used 72-pin connectors, which meant they could only be used for 32-bit addressing. Although modern SO-DIMMs are nearly on par with their DIMM counterparts, they still lag behind them in performance and capacity, pending miniaturization of the newer technology being applied on DIMMs.

SO-DIMM pin configurations:

  • 72-Pin SO-DIMM
  • 100-Pin SO-DIMM
    — SDRAM (PC-2100/2700)/EDO/firmware
  • 144-Pin SO-DIMM
    — SDRAM (PC-66/100/133/)/EDO
  • 200-Pin SO-DIMM
    — SDRAM (PC-2100/2700/3200) (PC2-3200/4200/5300/6400)
  • 204-Pin SO-DIMM
    — SDRAM (PC3-8500/10666)

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.